Field of the Invention
The present invention relates to a continuous variable valve duration apparatus and a control method using the same. More particularly, the present invention relates to a continuous variable valve duration apparatus that can change opening duration of a valve with a simple configuration in accordance with operational states of an engine.
Description of Related Art
In general, internal combustion engines generate power by receiving and burning air and fuel in a combustion chamber. An intake valve is operated by a camshaft, and air is charged into the combustion chamber while the intake valve is open. An exhaust valve is also operated by the camshaft, and air is discharged from the combustion chamber while the exhaust valve is open.
Optimal operation of the intake valve/exhaust valve, however, depends on the RPM of the engine. That is, an appropriate time for lifting or opening/closing the valves depends on the RPM of the engine. In order to implement an appropriate valve operation in accordance with the RPM of the engine, as described above, a CVVL (Continuously Variable Valve Lift) apparatus that has a plurality of shapes of cams operating valves or operates valves at different lifts in accordance with the RPM of an engine has been studied.
A CVVT (Continuous Variable Valve Timing) technique has been developed to adjust the opening duration of a valve, in which the timing of opening/closing a valve are simultaneously changed with the valve duration being fixed.
However, the CVVL or the CVVT has a problem in that the configuration is complicated and the manufacturing cost is high. Meanwhile, there is a limit in preventing knocking of an engine using the CVVT.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.